Battery pack retaining latch for cordless device

ABSTRACT

A battery retention latch (50, 140) comprises an annular ring member (52, 142), a release button (54, 172, 174) and a spring arm (156, 190, 192, 194, 196). The annular ring (52, 142) retains a battery pack (26) in a cordless device (20, 120) regardless of the annular orientation of the battery pack (26) about a casing axis. The spring arm (56, 190, 192, 194, 196) maintains the ring (52, 142) in a normally engaged position and upon depressing the push button (54, 172, 174), the battery (26) may be removed from the device (20, 120).

This is a continuation of U.S. patent application Ser. No. 08/289,158,filed Aug. 11, 1994, now U.S. Pat. No. 5,681,667.

FIELD OF THE INVENTION

The invention relates to cordless (i.e. battery operated) devices suchas portable electronic devices, toys, power tools or kitchen appliances.More particularly, the present invention relates to a battery packlatching ring to retain the pack in the device.

BACKGROUND OF THE INVENTION

For the consumer market, most cordless devices have a battery pack madeintegrally in the device housing because of reduced cost, increased userconvenience and sturdiness. However, because of the desire to provideconsumer devices with detachable packs, simplifying the recycling of thepacks, and the desire to provide a family of cordless devices using aninterchangeable pack and a single charger, there is a desire to use sucha battery pack. Also, it is desirable to retain the battery pack in thedevice such that the battery pack may be easily coupled with the deviceand readily removable from the device. Of course, these design goals arenot unique to consumer devices, but are equally desirable forprofessional cordless devices in which detachable packs have beenstandard for many years.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide animproved battery pack latch to retain the pack in a cordless deviceembodying the foregoing design objectives.

In accordance with one aspect of the invention, a battery pack retentionlatch comprises at least one annular member to couple witch the batteryto retain it in the device, a release button formed with the at leastone annular member, the release button is activated to move the annularmember to a release position to enable the battery to be removed fromthe device, and a spring member to bias the annular member between itscoupling or retention position and its release position. The springmember is coupled with the at least one annular member. Preferably, theat least one annular member is a continuous ring with the spring memberand release button positioned opposing one another on the ring. The ringis divided into four portions with the first portion adapted to engagethe battery pack to removably retain the battery pack in the device.Also, the spring member is an arm integrally formed with the first ringportion extending therefrom to bias the ring in a normally engagedposition in the device.

In accordance with a second aspect of the invention, the at least oneannular member is an open ring. Here, the annular ring has an overallopen figure eight configuration divided into two ring sections having acontinuous inner opening and open on one of its sides. Each ring sectionincludes a release button and a spring member and the spring and releasemember oppose one another on the ring sections. Each ring section has anoverall C shape with the Cs being connected to one another in opposingfashion (forming the open figure eight), continuous at one end and openat the other. Each of the C shaped ring sections includes an arcuateflange integrally formed with an engaging portion of the C shaped ringsection. The flange engages the battery pack to retain the battery packin a device on the latch. The spring member includes a pair of springarms extending from the engaging portion of the C shaped ring section.

In accordance with a third aspect of the invention, a cordless devicecomprises a cavity with a receptacle in the cavity, a battery packremovably located in the cavity with the battery pack including amechanism for electrically coupling with the receptacle and the deviceincluding a retention latch in accordance with either the first orsecond aspect of the invention described above.

In accordance with a fourth aspect of the invention, a cordless devicecomprises a cavity with a receptacle in the cavity, the receptacle isadapted to receive a battery and the device includes a retention latchin accordance with either the first or second aspect of the inventiondescribed above.

The cordless device includes at least one projection to support thespring member in its normally engaged position and to locate the latchwithin the device. The device also includes at least one pair ofopposing openings in it to enable grasping of the battery pack to removethe battery pack from the cordless device.

In accordance with a fifth aspect of the invention, a method of removinga battery from the device comprises providing a cordless device inaccordance with the third aspect, activating the release button andremoving the battery.

In accordance with a sixth aspect of the invention, a cap for a batterypack comprises a cylindrical wall with an exterior surface and aninterior diameter to fit onto the battery pack and a groove in theexterior surface to engage a retention latch in accordance with eitherthe first or second aspect of the invention described above.

Additional objects and advantages of the invention will be apparent fromthe detailed description of the preferred embodiment, the appendedclaims and the accompanying drawings or may be learned by practice ofthe invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate two embodiments of the presentinvention and together, with the description, serve to explain theprinciples of the invention. In the drawings, the same referencenumerals indicate the same parts.

FIG. 1 is a side view, partially in cross section, of a cordless devicein accordance with the present invention.

FIG. 2 is a cross sectional view of the cordless device of FIG. 1 alongline 2--2 thereof.

FIG. 3 is a perspective view of a retaining latch in accordance with thepresent invention.

FIG. 4 is a cross sectional view of FIG. 1 along line 4--4 thereof in anengaged position.

FIG. 5 is a view like FIG. 4, with the latching ring in a disengagedposition.

FIG. 6 is a rear plan view of the latch of FIG. 3.

FIG. 7 is a cross sectional view of FIG. 6 along line 7--7 thereof.

FIG. 8 is a side view partially in section of a second embodiment of acordless device in accordance with the present invention.

FIG. 9 is a side plan view, partially in section, of the cordless deviceof FIG. 8.

FIG. 10 is a perspective view of a second embodiment of a retaininglatch ring in accordance with the present invention.

FIG. 11 is a cross sectional view of FIG. 8 along line 11--11, with thelatch in an engaged position.

FIG. 12 is a view like that of FIG. 11 in a transition position.

FIG. 13 is a view like FIGS. 11 and 12 with the latch in a disengagedposition.

FIG. 14 is a front plan view of the latch in accordance with the presentinvention.

FIG. 15 is a cross sectional view of FIG. 14 along line 15--15 thereof.

FIG. 16 is a partial perspective view of the cordless device of FIG. 8.

FIG. 17 is a partial perspective view of the cordless device of FIG. 1.FIG. 18 is a perspective view of a cap in accordance with the presentinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment of the present invention is a cordless (i.e.battery operated) device, such as a portable electronic device, toy,kitchen appliance or power tool. Examples of such a device are acordless screw driver 20 and drill 120 as shown in FIGS. 1, 2 and 8, 9,respectively. The preferred embodiment, more particularly, is animproved retention latch 50, 140 to retain battery packs 26 in thedevice 20, 120.

As shown in FIGS. 1 and 2, in accordance with the present invention, acordless device 20, herein exemplified as an in-line screw driver,comprises a housing 24 to receive a battery pack 26, a motor (notshown), an output spindle 28, a gear train (not shown) intermediate themotor and spindle, and a receptacle 30 to electrically connect batterypack 26 to the motor through a motor control circuit (not shown)including on and off and speed control switch 32. Housing 24 furtherincludes a generally cylindrical cavity 34 and a handle portion 36 ofthe housing 24 to receive battery pack 26 in receptacle 30. Also, thehousing 24 includes a pair of opposing housing openings 38 and 40 whichenable removal of the battery pack 26 from the housing 24. Optionally, aspring 23 may be positioned in the housing cavity 34 to provide anejection force to remove the battery pack from the housing upon removalof the retention force.

According to one aspect of the invention, the battery pack 26 isremovably located in the cavity 34 and is electrically connectable tothe receptacle 30 regardless of the angular orientation of the batterypack 26 about a longitudinal axis of symmetry of the pack 26 (thisaspect of the invention is sometimes hereinafter referred to as theuniversal angular orientation feature). The pack 26 is thus easier touse and may be easily loaded in device 20 under adverse conditions suchas in dim light or in cramped quarters.

Battery pack 26 is fully described in U.S. patent application Ser. No.08/065,736 for "Battery Pack For Cordless Device", filed May 21, 1993,now abandoned, the specification and drawings of which are hereinexpressly incorporated by reference. Thus, a detailed description of thebattery pack 26 will not be given and only those elements which arenecessary for the description will be described.

Battery pack 26 comprises an elongated cylindrical tubular metal casing235 having opposed rear and forward ends 237 and 239. A plurality ofelectrically connected mechanically disconnected cells 241, 243, 244 aredisposed end to end in casing 235. For simplicity, pack 26 isillustrated in FIG. 2 with three cells 241, 243, 244. However, thepresent invention is equally applicable to packs including two or morecells. Each cell 241, 243, 244 has a cell can 241a, 243a, 244a forforming a first cell terminal and a button terminal 241b, 243b, 244bclosing one end of the cell and forming a second cell terminal. As isconventional, the first or cell can terminal 241a, 243a, 244a isnegative and the second or button terminal 241b, 243b, 244b is positive.The cells 241, 243, 244 are preferably nickel cadmium cells which arepreferred for high discharge rate applications (5 to 30 amps) such aspower tools and certain kitchen appliances. However, the presentinvention is also equally applicable to other rechargeable and primarycell couples such as nickel, metal hydride or primary alkaline cells.

The top 253 closes the casing forward end 239, is electrically connectedto button terminal 243b and forms a second pack terminal 254. Top 253 isradially symmetrical about the casing axis and defines a cavity 255 inthe casing forward end 239. A forwardly projecting nipple 257 formed onthe top 253 is fully recessed within cavity 255 and terminatesrearwardly to a forward edge of casing 235. Top 253 is electricallyconnected to and mechanically disconnected from forward cell 243 throughengagement with button terminal 243b. As will be appreciated, first andsecond pack terminals 246, 254 and 255 have opposite polarities(preferably, negative and positive, positive, respectively), are coaxialwith the casing axis and are located adjacent to the casing forward end239 and, for those reasons, pack 26 is easily connectable in thecordless device 20 with receptacle 30 regardless of the angularorientation of the pack 26 about the pack axis. To electrically insulateeach cell 241, 243, 244 from casing 235, the cells 241, 243, 244 areenclosed with an electrically insulated sleeve 277.

The cap 29 has a cylindrical wall 31 with an exterior surface and aninterior diameter to fit over the metal housing of the battery pack 26.The cap 29 is secured to the pack 26. The cylindrical wall 31 has anopen end 33 and a closed dome shaped end 35, however, the closed endcould likewise be open. The dome end 35 acts as a shock absorber in theevent the battery is dropped on a surface. Adjacent the open end 33 isan angled peripheral surface 25 on the external surface. The anglesurface 25 acts as a cam to enable passage of the cap 29. A latch keepergroove 27 is formed in the external surface of the cylindrical wall 31to provide an engaging recess for the retention latch 50, 140. Grippingmembers 37 are peripherally formed on the exterior surface of thecylindrical wall to aid in grasping of the cap 29 to remove the pack 26from the housing 24. The cap includes a bead 39 on its interior surfaceto secure it with a recess 281 in the pack casing 235.

The latch 50 is positioned transversely to the housing 24 to retain thebattery 26 within the cavity 34. The latch 50 couples with a latchkeeper groove 27 formed in the battery pack cap 29. The latch 50includes a latch ring 52, a push button 54 and a spring means 56 coupledto latch ring 52. In this embodiment, spring means 56 is preferablyconstituted by forwardly extending cantilevered spring arm 56 and is forbiasing latch ring 52 between a normally engaged position (FIG. 4) and arelease position (FIG. 5). Alternatively, spring means 56 may beconstituted by a torsion spring (not shown) coupled to one side of ring52 or may be constituted by a first forwardly extending cantileveredspring arm and a second rearwardly extending cantilevered spring arm.The use of forwardly and rearwardly extending arms would be desirable indevices that can accommodate a latch of greater length and would havethe advantage that the mounting of latch ring 52 would be more stableand balanced. The ring 52 is positioned within the housing 24 in agroove 60 formed by a pair of radially inwardly extending walls 62, 64in the housing 24 (FIG. 2). Also, the cantilevered spring arm 56 islocated in a recess 66 in the housing 24. The distal end 55 of thespring arm 56 is supported on a housing projection 68 to locate thelatch ring 52 in a normally engaged position. The spring constant ofspring arm 56 may be easily varied by changing its shape and thickness.Also, the spring force of spring arm 56 may be easily varied by changingthe height or location of projection 68. And thus, latch 50 may beeasily adapted to the requirements of the embodiment shown in FIGS. 1-7and other applications.

Turning to FIGS. 3 through 7, the latch 50 is shown. The latch ring 52includes ring portions 72, 74, 76 and 78. The first ring portion 72 actsas the battery engaging portion which engages the latch keeper groove 27formed in the battery pack cap 29. The spring arm 56 extends from thisportion 72 of the ring 52. The ring portions 74 and 76 are transitionportions and extend on each side of the continuous ring 52 and includereinforcement tabs. To guide movement of ring 52, each ring portion 74,76 has a flat outer surface 75, 77 in sliding engagement with arespective inner flat web between sidewalls 62, 64. Fourth ring portion78 opposes the first ring portion 72 and includes the unitarily formedpush button 54. As can be seen in the figures, the ring 52 has anelliptical shape with a first radius 71 defining the arc of the firstring portion 72 with substantially parallel arcs or lines on the ringportions 74 and 76 and a second radius 77 defining the arc of the fourthring portion 78. The radii 71, 77 of the first and fourth ring portions72 and 78 are different such that the second 74, third 76 and fourth 78ring portions do not engage the battery latch keeper groove 27 in anengaged or disengaged position. Also, this design aids in the movementof the latch ring 56 such that when the push button 54 is pushedradially of the housing 24, the ring 52 is moved laterally downwardwithout bowing its annular portion and is disengaged by flexing springarm 56 in the housing recess 66. Thus, ring 52 is located in thedisengaged position shown in FIG. 5. The annular portion of the ring 52is guided by and prevented from bowing by the web between side walls 62,64 of the housing 24, as seen in FIG. 2. Further, flat surfaces 75, 77aid in reducing friction and prevent rotation of ring 52 about thelongitudinal axis of handle 36.

The engagement ring portion 72 includes an angled cam surface 82 whichassists to enable the battery 26 to pass through the ring 52 as thebattery cap 29 contacts the cam surface 82, assisting the battery 26 toslide through the latch opening 51.

The latch 50 is ordinarily formed from a polymeric material such asacetel forming the latch 50 as a unitary one piece device. However, thelatch 50 may be manufactured from several different parts piecedtogether to form a desired latch member. Also, the latch could be madeof a metallic material or a metallic material coated with a polymericmaterial.

The distal end 55 of the arm 56 is supported on the housing projection68 to locate the latch ring 52 in a normally engaged position (FIGS. 1,2 and 4). Here, the first ring portion 72 of the ring 52 is engaged onor latched in the cap groove 27. When the push button 54 is pushedradially inward of the housing, ring 52 is moved laterally downward(without bowing its annular position) and is disengaged by flexingspring arm 56 into the recess 66. Thereby, ring 52 is located in thedisengaged position shown in FIG. 6. The annular portion of the ring 52is prevented from bowing by the radially inward housing web between sidewalls 62, 64 (FIG. 2).

To insert the battery pack 26 into the housing 24, the battery pack 26is inserted into the housing 24 in any angular orientation and is freelyslidable in the housing cavity 34 until the first latch ring portion 72engages the forward tapered rim 25 of the battery cap 29. The rim 25functions as a camming surface with the camming surface 82 of the firstring portion 72 and bends arm 56 outwardly as battery pack 26 ismanually forced into the cavity 34. In this manner, ring 52 slides overrim 25 and is biased resiliently inward into the cap groove 27 by springarm 56 to assume the engaged position shown in FIGS. 1, 2 and 4. Todisengage battery pack 26, the release button 54 is pushed radiallyinwardly, normally by the user's thumb, to flex spring arm 56 into thehousing recess 66. Thereafter, battery pack 26 can be pulled axiallyoutwardly from the cavity 34 by the index finger on the same hand of theuser by gripping or grasping the gripping members 37 of the cap 29through one of the opposed housing openings 323, 40.

In accordance with another feature of the present invention, cordlessdevice 120, herein exemplified as a drill, comprises a housing 122 forreceiving battery packs 26, a motor, not shown, an outer spindle 124, agear train (not shown) intermediate the motor and spindle 124, and areceptacle 126 for electrically connecting the battery packs 26 to themotor through a motor control circuit (not shown), including on/off andspeed control switch 128. springs (not shown) like the one previouslydescribed could be used to provide an ejection force. Housing 122further includes cylindrical cavities 130 and 132 in a handle portion134 of the housing 122 to receive battery packs 26 in receptacle 128.The battery packs 26 are the same as those previously defined with theinvention being directed to a retention latch 140 positioned within thehousing handle 134.

The latch 140 comprises a latch double ring 142 mounted in the drillhandle 134 and latch keeper grooves 27 formed in the battery pack caps29. The double ring 142 is located transversely of the handle 134 and iscoupled to a spring means 144, 146 for biasing latch ring 142 between anormally engaged position (FIG. 11) and a release position (FIG. 12). Inthis embodiment, spring means 144, 146 is preferably constituted by apair of forked cantilevered spring arms 144, 146. As in the case of theembodiment shown in FIGS. 1-7, the spring means may also be constitutedby a torsion spring or by forwardly and rearwardly extending springarms. The ring 142 is seated in a transverse channel 150 defined by apair of radially extending parallel spaced walls 154 and 156 and islaterally slidable in a plane perpendicular to the battery pack axes.The spring arms 144 and 146 are supported on projections 158 on theinterior of the handle 134 to locate the latch ring in a normallyengaged position, as shown in FIGS. 8, 9 and 11.

As shown in the figures, the double ring 142 has an overall open figureeight configuration which is open inside the annular regions. Each ring160, 162 is C shaped, being connected at one end 164, 166 and being freeat the other 168, 170 The free ends 168, 170 of the rings 160, 162include an integrally or unitarily formed push button 172, 174 whichenables movement of the latch rings 160, 162. Opposing the push buttons172, 174 are engagement portions 176 and 178 of the C shaped rings 160,162. The engagement portions 176 and 178 include integrally or unitarilyformed arcuate flanges 182 and 184 that are latched, respectively, inthe battery pack grooves 27. The spring arms 144, 146 extend from theengaging portion 176, 178 of the C shaped rings 160, 162. Thus, the arms144, 146 also oppose the push button members 172, 174. Further,preferably each spring arm 144, 146 includes a pair of arms 190, 192,194, 196. As mentioned above, the pair of arms 190, 192, 194, 196 aresupported on projections 158 to locate the latch ring 142 in a normallyengaged position as shown in FIG. 11.

As seen in FIGS. 11 and 12, the pair of integrally formed arcuateflanges 182, 184 are latched, respectively, in cap grooves 27. The latch140 is designed such that the battery packs 26 can be selectivelyremoved one at a time. To disengage one of the packs 26, the push button172 is pushed laterally towards the battery pack 26 by the user's thumbto disengage the flange 182 from the cap groove 27 by primarilyresiliently bending the spring arms 190, 192. The annular portions ofthe ring 142 are designed such that the bending of the annular portions160 is slight when flexing the spring arms 190, 192. Also, the ring 160may pivot slightly about a point 200 when disengaging the flange 182from the groove 27. Thus, the battery 26 may be removed from the cavity130 by gripping or grasping with the index finger of the same hand thegripping member 37 of the cap 29 through one of the opposed housingopenings 202, 204. Regardless, the other flange 184 remains engaged inthe groove 27 when the push button 172 is pushed to the disengagementposition. The other battery pack 26 is removable from the handle 134 bypushing the other push button 174 to disengage the flange 184 from thegroove 27 in an analogous manner. Likewise, the cap 29 would be grippedwith an index finger through one of the opposing housing openings 206,208.

To insert the battery packs 26 in the handle 134, the pack 26 isinserted into the handle 134 in any angular orientation and is freelyslidable in the handle cavities 130, 132 until the flange 182, 184engages the forwardly tapered rim 25 of the cap 29. The cap rim 25functions as a camming surface and bends the spring arm 190, 192, 194,196 outwardly as the battery pack 26 is manually forced into the cavity130, 132. In this manner, flange 182, 184 of the ring 160, 162 slidesover the cap rim 25 and is resiliently biased inward into the cap groove27 by the spring arm 190, 192, 194, 196 and somewhat by the other springarm 194, 196, 190, 192 to assume the engaged positioned shown in FIG.11. The other battery pack 26 may be inserted into the cavity 132, 130in the handle 134 in an analogous manner.

As mentioned above, the latch 140 can be manufactured from a plethora ofmaterials, including polymeric materials such as nylon, metallicmaterials or metallic coated materials. Also, the latch 140 may be aunitary one piece device or it may be formed by several independentmembers.

By eliminating retention latch from the battery itself and positioningthe latch within the housing, the batteries may be smaller and are ableto nest with one another in a group in close proximity to one another.Also, the latch is more durable when enclosed in the housing,prohibiting easy break off like that which occurs when the latch is onthe battery. Other advantages will be apparent to those skilled in theart.

It will be recognized that although latches 50, 140 have been describedas preferably generally annular or circular, other configurations may beused consistent with the geometry of the device in which the latch isused. For example, rectangular and octagonal configurations may be used.Such configurations may also be open to form a generally C-shapedconfiguration, if desired.

It will be apparent to those skilled in the art that variousmodifications and variations may be made in the cordless device andlatch of the present invention without departing from the scope or thespirit of the present invention. Thus, it is intended that the presentinvention cover these modifications and variations provided they comewithin the scope of the appended claims and their equivalents.

What is claimed is:
 1. A retention latch adapted to be positioned withina device for retaining a battery in the device, said retention latchcomprising:at least one annular member, said annular member adapted forengaging with the battery; a release member coupled with said at leastone annular member, said release member adapted to be activated to movesaid annular member to a release position to enable the battery to beremoved from the device; and means for maintaining said annular memberbetween a normally engaged position and its release position.
 2. Theretention latch according to claim 1, wherein said at least one annularmember is an open ring.
 3. A cordless device comprising:a cavity; areceptacle in the cavity; a battery pack removably located in thecavity, said battery pack including means for electrically coupling withsaid receptacle; and a latch for retaining said battery, in said cavity,said latch including at least one annular member, said annular memberengaging with the battery to retain said battery in said cavity; arelease member coupled with said at least one annular member, saidrelease member adapted to be activated to move said annular member to arelease position to enable the battery to be removed from the device;and means for maintaining said annular member between a normally engagedposition and its release position.
 4. The device according to claim 3,further including at least one pair of opposed openings in said cordlessdevice for enabling grasping of said battery for removal from saidcordless device.
 5. The retention latch according to claim 3, whereinsaid at least one annular member is an open ring.
 6. A cordless devicecomprising:a cavity; a receptacle, said receptacle adapted to receive abattery; and a latch adapted for retaining the battery in said cavity,said latch including at least one annular member, said annular memberadapted for engaging with the battery to retain the battery in saidcavity; a release member coupled with said at least one annular member,said release member adapted to be activated to move said annular memberto a release position to enable the battery to be removed from thedevice; and means for maintaining said annular member between a normallyengaged position and its release position.
 7. The retention latchaccording to claim 6, wherein said at least one annular member is anopen ring.
 8. A method for removing a battery from a cordless devicecomprising:providing a cordless device having a housing, a cavity forreceiving a battery in said housing, and at least one pair of opposingopenings in said housing extending into said cavity, and a latch in thecordless device for retaining the battery in the cavity, said latchincluding at least one annular member to engage the battery, a releasemember coupled with the annular member, and a means for maintaining saidannular member between a normally engaging position and its releaseposition; activating said release member to move said annular memberfrom its normally engaged position to its release position; removing thebattery from the device cavity.